• Advances in Traditional Medicine
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• 제1권1호
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• pp.28-36
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• 2000

Effects of hesperetin and naringenin on the concentration of triacylglycerol in the serum and liver were studied in male golden hamster fed with the semipurified diet containing at 1% level of them for 3 weeks. The concentration of triacylglycerol in serum of the naringenin group decreased by 31%, whereas that in liver increased by 37% compared to the control group. The concentration of triacylglycerol in the serum and liver of the hesperetin group was slightly lower than the control group. The activity of microsomal phosphatidate phosphohydrolase in the liver, which is a key enzyme for biosynthesis of triacylglycerol, was significantly inhibited in the hesperetin group, whereas it was not affected in the naringenin group. The effect of hesperetin on phosphatidate phosphohydrolase was also measured in vitro. Hesperetin decreased the activity of phosphatidate phosphohydrolase with a dose-dependent manner. Both naringenin and hesperetin did not statistically affect the daily food consumption, body weight, liver weight, and total cholesterol in the serum. The observation accounts for the hypotriglyceridemic effect of hesperetin in the hyperlipidemic hamster.

• Parasites, Hosts and Diseases
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• 제37권4호
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• pp.271-275
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• 1999

Pneumocystis carinii is the most important opportunistic pathogen of humans in the world. Pneumocystis carinii is experimentally detected in the lungs of rats, mice, rabbits, and monkeys, however, the organisms from different mammals are identical in microscopic morphology. The present study tried to find out more mammalian hosts of P. carinii and also to differentiate the organisms from different mammals by karyotyping. Rats, mice, hamsters, rabbits, cats, and dogs were successfully infected by P. carinii, but guinea pigs and pigs were not. Karyotype of P. carinii from rabbits showed similar size range of chromosomes with that of the prototype, but in different pattern. The patterns from cats and dogs were also different from that of rats. The present study confirms that cats and dogs are infected by P. carinii and at least total three karyotype strains of P. carinii are proven in Korea.

• Korean Journal of Food Science and Technology
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• 제43권6호
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• pp.659-674
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• 2011

Saccharin was reported to cause urinary bladder cancer in male rats when fed at high doses in a two-generation study, which led to a ban on the use of saccharin in Canada. However, no carcinogenic effect has been observed in other animal experiments conducted with mice, hamsters, or monkeys. Furthermore, numerous epidemiological studies have indicated that there was no relationship between saccharin consumption and the risk of bladder cancer in the human population. Sodium saccharin produces urothelial bladder tumors in rats by the formation of a urinary calcium phosphatecontaining precipitate, which is not relevant to humans because of critical interspecies difference in urine composition. Consequently, in 1999 IARC (International Agency for Research on Cancer) concluded that saccharin and its salts cannot be classified as to their carcinogenicity in humans. In 2010, the EPA (Environmental Protection Agency) of the United States removed saccharin from its list of hazardous substances. It is expected that the use of saccharin in foods might be expanded because saccharin is currently considered safe.

• Journal of Microbiology and Biotechnology
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• 제25권8호
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• pp.1234-1240
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• 2015

Heat shock RNA 1 (HSR1) is described as a "eukaryotic heat-sensing noncoding RNA" that regulates heat shock response in human and other eukaryotic cells. Highly conserved HSR1 sequences have been identified from humans, hamsters, Drosophila, Caenorhabditis elegans, and Arabidopsis. In a previous study, however, it was suggested that HSR1 had originated from a bacterial genome. HSR1 showed no detectible nucleotide sequence similarity to any eukaryotic sequences but harbored a protein coding region that showed amino-acid sequence similarity to bacterial voltage-gated chloride channel proteins. The bacterial origin of HSR1 was not convincible because the nucleotide sequence similarity was marginal. In this study, we have found that a genomic contig sequence of Comamonas testosteroni strain JL14 contained a sequence virtually identical to that of HSR1, decisively confirming the bacterial origin of HSR1. Thus, HSR1 is an exogenous RNA, which can ectopically trigger heat shock response in eukaryotes. Therefore, it is no longer appropriate to cite HSR1 as a "eukaryotic functional noncoding RNA."

• Parasites, Hosts and Diseases
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• 제53권5호
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• pp.627-639
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• 2015

Metagonimus yokogawai (Katsurada, 1912) Katsurada, 1912 (Trematoda: Heterophyidae) is parasitic in the small intestine of mammals including man and birds in Far Eastern Russia, Korea, Japan, China, and Taiwan. In the present study, the metacercariae and adults of M. yokogawai were redescribed to designate a neotype of this fluke together with reviews of previous studies including study histories from the first discovery to now. We particularly, attempted to review the study histories and morphological descriptions of M. yokogawai for the species validity, and compared with the morphological characteristics and life cycles of the closely related species, Metagonimus takahashii and Metagonimus miyatai. Finally, we proposed a differential key for the 8 known Metagonimus species distributed in East Asia. Metacercariae were obtained from the body muscles of sweetfish (Plecoglossus altivelis) collected in the Asahi River at Takebe-cho, Kita-ku, Okayama City, Okayama Prefecture, Japan. Adults were recovered from the small intestine of Syrian golden hamsters, to which the metacercariae had been fed 14 days before. A neotype was selected out of the present adult specimens. The Asahi River at Takebo-cho became the type locality of M. yokogawai. In conclusion, the present review shows that M. yokogawai, M. takahashii, and M. miyatai are valid and discriminated by means of morphological characteristics.

• Archives of Pharmacal Research
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• 제26권8호
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• pp.659-665
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• 2003

We have studied the effect of rhEGF on the buccal mucosal ulcer healing. rhEGF was rapidly degraded upon incubation with the hamster buccal mucosal homogenates; The degradation of rhEGF was significantly inhibited by sodium lauryl sulfate (SLS). Eudispert hv hydrogel and Polycarbophil 974P hydrogel were prepared for rhEGF delivery and their mucoadhesiveness was measured by the $Instron^R$ method. The mucoadhesive force of Eudispert hv was significantly greater than that of Polycarbophil 974P. Moreover, rhEGF in Eudispert hv hydrogel remained stable for about 2 months. To evaluate the ulcer healing effect of rhEGF, the buccal mucosal ulcer was induced in golden hamsters using acetic acid. At 24 h after administration of rhEGF/Eudispert hv hydrogel, the ulcerous area was decreased compared with rhEGF solution and, as a result, the curative ratio was $36.8\pm5.68$%. By the addition of SLS (0.5%) to Eudispert hv hydrogel, the curative ratio increased 1.5 times. The mechanism of the action was probably due to a combination of protection of the drug against proteases present in mucosa and prolongation of the release of rhEGF from the formulation at the site of action.

• Development and Reproduction
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• 제26권3호
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• pp.107-115
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• 2022

Kisspeptins, products of KISS1 gene, are ligands of the G-protein coupled receptor (GPR54), and the kisspeptin-GPR54 signaling has an important role as an upstream regulator of gonadotropin releasing hormone (GnRH) neurons. Interestingly, extrahypothalamic expressions of kisspeptin/GPR-54 in gonads have been found in primates and experimental rodents such as rats and mice. Hamsters, another potent experimental rodent, also have a kisspeptin-GPR54 system in their ovaries. The presence of testicular kisspeptin-GPR54 system, however, remains to be solved. The present study was undertaken to determine whether the kisspeptin is expressed in hamster testis. To do this, reverse transcription-polymerase chain reactions (RT-PCRs) and immunohistochemistry (IHC) were employed. After the nest PCR, two cDNA products (320 and 280 bp, respectively) were detected by 3% agarose gel electrophoresis, and sequencing analysis revealed that the 320 bp product was correctly amplified from hamster kisspeptin cDNA. Modest immunoreactive (IR) kisspeptins were detected in Leydig-interstitial cells, and the weak signals were detected in germ cells, mostly in round spermatids and residual bodies of elongated spermatids. In the present study, we found the kisspeptin expression in the testis of Syrian hamster. Further studies on the local role(s) of testicular kisspeptin are expected for a better understanding the physiology of hamster testis, including photoperiodic gonadal regression specifically occurred in hamster gonads.

• The Korean Journal of Zoology
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• 제11권3호
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• pp.99-102
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• 1968

Giving unprocessed ginseng to the hamster(Mesocricetus auratus) a gram per day for 25 days, I obtained the following results: 1. A significant increase in hemoglobin has been registered as a result of the supply of ginseng. 2. A significant increase in the serum-total protein has also been recorded after 15th day of the supply of ginseng. 3. Outwardly, it shows A/G ratio gradually increasing from the 10th day following the supply of ginseng. But the significant increase is shown after 25th day of ginseng supply. This means that the component of albumin has increased more than that of globulin. In short, the Hb and total protein and albumin in serum increase as a result of 25 days of giving ginseng to the hamsters.

• IMMUNE NETWORK
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• 제21권2호
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• pp.12.1-12.17
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• 2021

Coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Since the emergence of SARS-CoV-2 in the human population in late 2019, it has spread on an unprecedented scale worldwide leading to the first coronavirus pandemic. SARS-CoV-2 infection results in a wide range of clinical manifestations from asymptomatic to fatal cases. Although intensive research has been undertaken to increase understanding of the complex biology of SARS-CoV-2 infection, the detailed mechanisms underpinning the severe pathogenesis and interactions between the virus and the host immune response are not well understood. Thus, the development of appropriate animal models that recapitulate human clinical manifestations and immune responses against SARS-CoV-2 is crucial. Although many animal models are currently available for the study of SARS-CoV-2 infection, each has distinct advantages and disadvantages, and some models show variable results between and within species. Thus, we aim to discuss the different animal models, including mice, hamsters, ferrets, and non-human primates, employed for SARS-CoV-2 infection studies and outline their individual strengths and limitations for use in studies aimed at increasing understanding of coronavirus pathogenesis. Moreover, a significant advantage of these animal models is that they can be tailored, providing unique options specific to the scientific goals of each researcher.

• Korean Journal of Veterinary Research
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• 제21권2호
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• pp.73-79
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• 1981

In order to know the morphology and the function of the fat-storing cells (FSC) of the squirrels which were captured at the Pal-Gong mountain near Taegu in December, 1980 (Group A) and May, 1981 (Group B), respectively, the light and electron microscopic observations were conducted on the liver of the squirrels. The results obtained are as follows: 1. Light microscopically, the size of the lipid droplets in the FSC of group A was uniformly larger than those in the cells of group B, and number of the droplets in the FSC of group A was less than those in the cells of group B, The distribution of the FSC of group A was mainly perilobular area while those of group B was centrolobular and midzonal areas. In this point of view, the FSC of the squirrels was similar to those cells of the hamsters. 2. Electron microscopically, general morphology of the sqirrel's FSC was accorded with those of the other mammals. However, the rouph surfaced endoplasmic reticulum in the FSC of group B was more dilated than those in the cells of group A, and more lipid droplets and pinocytopic vesicles were observed in the FSC of group B than those in the cells of group A. 3. From the above evidences, it could be suggested that the metabolic rates in the FSC of the squirrels collected in the spring were higher than those in the cells of the animals collected in the winter.